P3.1: iOS goldens @2x + PNG optimizer + Makefile record/verify targets

- SnapshotGalleryTests rendered at displayScale: 2.0 (was native 3.0)
  → 49MB → 15MB (~69% reduction)
- Records via SNAPSHOT_TESTING_RECORD=1 env var (no code edits needed)
- scripts/optimize_goldens.sh runs zopflipng (or pngcrush fallback)
  over both iOS and Android golden dirs
- scripts/{record,verify}_snapshots.sh one-command wrappers
- Makefile targets: make {record,verify,optimize}-snapshots

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Makefile

@@ -0,0 +1,55 @@
+# Makefile for HoneyDue KMM — wraps the long-form commands you actually
+# use every day. If you find yourself copy/pasting a command twice, it
+# belongs here.
+#
+# Quick reference
+# ---------------
+#   make verify-snapshots     # fast; run on every PR, CI runs this
+#   make record-snapshots     # slow; regenerate baselines after UI change
+#   make optimize-goldens     # rarely needed — record-snapshots runs this
+#
+.PHONY: help record-snapshots verify-snapshots optimize-goldens \
+        record-ios record-android verify-ios verify-android
+
+help:
+	@echo "HoneyDue KMM — common tasks"
+	@echo ""
+	@echo "  make verify-snapshots    Verify iOS + Android parity goldens (CI gate)"
+	@echo "  make record-snapshots    Regenerate iOS + Android goldens + optimize"
+	@echo "  make optimize-goldens    Run the PNG optimizer across both directories"
+	@echo ""
+	@echo "  make verify-ios          Verify just the iOS gallery"
+	@echo "  make verify-android      Verify just the Android gallery"
+	@echo "  make record-ios          Regenerate just the iOS gallery"
+	@echo "  make record-android      Regenerate just the Android gallery"
+	@echo ""
+
+# ---- Parity gallery (combined) ----
+
+# Regenerate every parity-gallery golden (iOS + Android) and shrink the
+# output PNGs. Slow (~3 min); run after intentional UI changes only.
+record-snapshots:
+	@./scripts/record_snapshots.sh
+
+# Verify current UI matches committed goldens. Fast (~1 min). PR gate.
+verify-snapshots:
+	@./scripts/verify_snapshots.sh
+
+# Optimize every PNG golden in-place (idempotent). Usually invoked
+# automatically by record-snapshots; exposed here for one-off cleanup.
+optimize-goldens:
+	@./scripts/optimize_goldens.sh
+
+# ---- Parity gallery (single platform) ----
+
+record-ios:
+	@./scripts/record_snapshots.sh --ios-only
+
+record-android:
+	@./scripts/record_snapshots.sh --android-only
+
+verify-ios:
+	@./scripts/verify_snapshots.sh --ios-only
+
+verify-android:
+	@./scripts/verify_snapshots.sh --android-only

iosApp/HoneyDueTests/SnapshotGalleryTests.swift

@@ -25,9 +25,26 @@
 //
 //  Recording goldens
 //  -----------------
-//  Set `isRecording = true` in `setUp()`, run the target, then flip back to
+//  Preferred: `make record-snapshots` (or `./scripts/record_snapshots.sh
-//  `false` before committing. CI fails the build if a screen diverges from
+//  --ios-only`). The script exports `SNAPSHOT_TESTING_RECORD=1` in the
-//  its golden by more than the precision threshold.
+//  xcodebuild env, deletes the old `__Snapshots__/SnapshotGalleryTests`
+//  directory, runs the target, then invokes the shared PNG optimizer.
+//
+//  Manual override: set the `SNAPSHOT_TESTING_RECORD` env var to `1` in
+//  the Xcode scheme's Test action (Edit Scheme → Test → Arguments →
+//  Environment Variables) and re-run the test target. CI fails the
+//  build if a screen diverges from its golden by more than the
+//  precision threshold.
+//
+//  Rendering scale
+//  ---------------
+//  We force `displayScale: 2.0` on every snapshot. The iPhone 15 /
+//  iPhone 13 simulators default to the device's native 3x, which on a
+//  full-screen gradient-heavy SwiftUI view produced 800–1000 KB PNGs
+//  per image. @2x halves the linear dimensions (2.25x fewer pixels) and
+//  is still plenty to catch layout regressions. Combined with
+//  `scripts/optimize_goldens.sh` (zopflipng / pngcrush) this keeps us
+//  under the 150 KB per-image budget enforced by CI.
 //
 
 @preconcurrency import SnapshotTesting
@@ -39,8 +56,14 @@ import ComposeApp
 @MainActor
 final class SnapshotGalleryTests: XCTestCase {
 
-    // Flip to true locally, run the scheme, revert, commit.
+    // Record mode is driven by the `SNAPSHOT_TESTING_RECORD` env var so
-    private static let recordMode: SnapshotTestingConfiguration.Record = .missing
+    // `scripts/record_snapshots.sh` can flip it without mutating this file.
+    // When the var is unset/empty we only write missing goldens (`.missing`)
+    // so local dev runs never silently overwrite committed PNGs.
+    private static var recordMode: SnapshotTestingConfiguration.Record {
+        let env = ProcessInfo.processInfo.environment["SNAPSHOT_TESTING_RECORD"] ?? ""
+        return (env == "1" || env.lowercased() == "true") ? .all : .missing
+    }
 
     override func invokeTest() {
         withSnapshotTesting(record: Self.recordMode) {
@@ -63,6 +86,12 @@ final class SnapshotGalleryTests: XCTestCase {
     private static let pixelPrecision: Float = 0.97
     private static let perceptualPrecision: Float = 0.95
 
+    /// Force @2x rendering regardless of the simulator device's native
+    /// `displayScale`. See the class-level "Rendering scale" comment for
+    /// rationale. 2.0 keeps PNGs under the size budget without sacrificing
+    /// the structural detail our parity gallery cares about.
+    private static let forcedDisplayScale: CGFloat = 2.0
+
     private func snap<V: View>(
         _ name: String,
         file: StaticString = #filePath,
@@ -80,7 +109,10 @@ final class SnapshotGalleryTests: XCTestCase {
                 precision: Self.pixelPrecision,
                 perceptualPrecision: Self.perceptualPrecision,
                 layout: .device(config: .iPhone13),
-                traits: .init(userInterfaceStyle: .light)
+                traits: .init(traitsFrom: [
+                    UITraitCollection(userInterfaceStyle: .light),
+                    UITraitCollection(displayScale: Self.forcedDisplayScale),
+                ])
             ),
             named: "\(name)_light",
             file: file,
@@ -93,7 +125,10 @@ final class SnapshotGalleryTests: XCTestCase {
                 precision: Self.pixelPrecision,
                 perceptualPrecision: Self.perceptualPrecision,
                 layout: .device(config: .iPhone13),
-                traits: .init(userInterfaceStyle: .dark)
+                traits: .init(traitsFrom: [
+                    UITraitCollection(userInterfaceStyle: .dark),
+                    UITraitCollection(displayScale: Self.forcedDisplayScale),
+                ])
             ),
             named: "\(name)_dark",
             file: file,

scripts/optimize_goldens.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+#
+# optimize_goldens.sh — recursively optimize PNG goldens in-place.
+#
+# Runs after each `record` pass for both iOS and Android parity galleries.
+# Removes unnecessary PNG chunks (textual metadata, ancillary palette
+# entries) and re-encodes the image with a better DEFLATE strategy so the
+# image bytes on disk drop by 15–40% without touching a single pixel.
+#
+# Dependencies
+# ------------
+#   zopflipng   (preferred — brute-force DEFLATE, best compression)
+#   pngcrush    (fallback — faster, smaller savings)
+#
+# Install on macOS:
+#   brew install zopfli pngcrush
+#
+# The script never fails if the tools are missing: it warns and exits 0,
+# leaving the goldens untouched. CI's size-gate will still fail loudly if
+# the PNGs would bust the 150 KB budget.
+#
+# Usage
+# -----
+#   ./scripts/optimize_goldens.sh                 # default dirs (iOS + Android)
+#   ./scripts/optimize_goldens.sh path1 path2     # specific dirs only
+#
+# Idempotent — re-running on already-optimized PNGs is a no-op.
+#
+set -euo pipefail
+
+DIRS=("$@")
+if [ ${#DIRS[@]} -eq 0 ]; then
+    DIRS=(
+        "iosApp/HoneyDueTests/__Snapshots__"
+        "composeApp/src/androidUnitTest/roborazzi"
+    )
+fi
+
+tool=""
+if command -v zopflipng >/dev/null 2>&1; then
+    tool="zopflipng"
+elif command -v pngcrush >/dev/null 2>&1; then
+    tool="pngcrush"
+else
+    echo "WARNING: neither zopflipng nor pngcrush is installed — skipping PNG optimization."
+    echo "  Install with: brew install zopfli pngcrush"
+    exit 0
+fi
+
+echo "optimize_goldens: using ${tool}"
+
+count=0
+saved=0
+for dir in "${DIRS[@]}"; do
+    if [ ! -d "$dir" ]; then
+        continue
+    fi
+    while IFS= read -r -d '' png; do
+        before=$(stat -f%z "$png" 2>/dev/null || stat -c%s "$png")
+        if [ "$tool" = "zopflipng" ]; then
+            # -y  : overwrite without prompt
+            # --lossy_transparent : allow color rewrite under alpha=0 for extra savings
+            zopflipng -y --lossy_transparent "$png" "$png" >/dev/null 2>&1 || true
+        else
+            # -ow : overwrite-in-place; -q : quiet
+            pngcrush -q -ow "$png" >/dev/null 2>&1 || true
+        fi
+        after=$(stat -f%z "$png" 2>/dev/null || stat -c%s "$png")
+        saved=$((saved + before - after))
+        count=$((count + 1))
+    done < <(find "$dir" -name '*.png' -print0)
+done
+
+if [ "$count" -eq 0 ]; then
+    echo "optimize_goldens: no PNGs found in: ${DIRS[*]}"
+    exit 0
+fi
+
+# Print a human-readable summary. `bc` is standard on macOS / most linuxes.
+mb=$(echo "scale=2; $saved/1048576" | bc)
+printf "optimize_goldens: %d PNGs processed, saved %.2f MB (%s)\n" "$count" "$mb" "$tool"

scripts/record_snapshots.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+#
+# record_snapshots.sh — regenerate every parity-gallery golden in one pass.
+#
+# Use this after an intentional UI change (new color token, redesigned
+# layout, etc.) so the committed baseline matches the new look. Reviewers
+# see the PNG diff alongside your code change in the PR — that dual-diff
+# is the whole point of the parity gallery.
+#
+# Usage
+# -----
+#   ./scripts/record_snapshots.sh                # iOS + Android
+#   ./scripts/record_snapshots.sh --ios-only
+#   ./scripts/record_snapshots.sh --android-only
+#
+# Pipeline
+# --------
+#   1. (Android) `./gradlew :composeApp:recordRoborazziDebug`
+#   2. (iOS)     Delete iosApp/HoneyDueTests/__Snapshots__/SnapshotGalleryTests,
+#                set SNAPSHOT_TESTING_RECORD=1, run xcodebuild test for
+#                SnapshotGalleryTests. The env var is read by
+#                SnapshotGalleryTests.swift to flip SnapshotTesting.record
+#                between `.missing` (default — safe) and `.all` (overwrite).
+#   3. Run `scripts/optimize_goldens.sh` across both golden directories to
+#      shrink the fresh PNGs.
+#
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+ROOT="$(pwd)"
+
+platform="both"
+for arg in "$@"; do
+    case "$arg" in
+        --ios-only)     platform="ios" ;;
+        --android-only) platform="android" ;;
+        -h|--help)
+            sed -n '3,18p' "$0"
+            exit 0
+            ;;
+        *)
+            echo "usage: $0 [--ios-only|--android-only]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+# ---------- Android ----------
+if [ "$platform" = "both" ] || [ "$platform" = "android" ]; then
+    echo "==> Recording Android goldens…"
+    ./gradlew :composeApp:recordRoborazziDebug
+fi
+
+# ---------- iOS ----------
+if [ "$platform" = "both" ] || [ "$platform" = "ios" ]; then
+    echo "==> Recording iOS goldens…"
+    rm -rf iosApp/HoneyDueTests/__Snapshots__/SnapshotGalleryTests
+    (
+        cd iosApp
+        # SNAPSHOT_TESTING_RECORD=1 flips SnapshotTesting.isRecording to
+        # `.all` (see SnapshotGalleryTests.swift).
+        SNAPSHOT_TESTING_RECORD=1 xcodebuild test \
+            -project honeyDue.xcodeproj \
+            -scheme HoneyDue \
+            -destination "${IOS_SIM_DESTINATION:-platform=iOS Simulator,name=iPhone 17,OS=latest}" \
+            -only-testing:HoneyDueTests/SnapshotGalleryTests \
+            2>&1 | tail -30
+    )
+fi
+
+# ---------- Optimize ----------
+echo "==> Optimizing PNGs…"
+"$ROOT/scripts/optimize_goldens.sh"
+
+# ---------- Parity HTML (P4 follow-up) ----------
+if [ -x "$ROOT/scripts/build_parity_gallery.py" ]; then
+    echo "==> Regenerating parity HTML gallery…"
+    python3 "$ROOT/scripts/build_parity_gallery.py"
+else
+    echo "==> (parity HTML generator not yet present — skipping)"
+fi
+
+echo "==> Done. Review the PNG diff with your code change before committing."

scripts/verify_snapshots.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+#
+# verify_snapshots.sh — verify every parity-gallery golden matches the
+# current code. Use as a pre-commit / CI gate.
+#
+# Exits non-zero if either platform's gallery drifts from its committed
+# baseline. Diff artifacts land under each platform's usual report dir:
+#   Android:  composeApp/build/outputs/roborazzi/
+#   iOS:      ~/Library/Developer/Xcode/DerivedData/.../HoneyDueTests/
+#
+# Usage
+# -----
+#   ./scripts/verify_snapshots.sh               # both platforms
+#   ./scripts/verify_snapshots.sh --ios-only
+#   ./scripts/verify_snapshots.sh --android-only
+#
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+platform="both"
+for arg in "$@"; do
+    case "$arg" in
+        --ios-only)     platform="ios" ;;
+        --android-only) platform="android" ;;
+        -h|--help)
+            sed -n '3,14p' "$0"
+            exit 0
+            ;;
+        *)
+            echo "usage: $0 [--ios-only|--android-only]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+# ---------- Android ----------
+if [ "$platform" = "both" ] || [ "$platform" = "android" ]; then
+    echo "==> Verifying Android goldens…"
+    ./gradlew :composeApp:verifyRoborazziDebug
+fi
+
+# ---------- iOS ----------
+if [ "$platform" = "both" ] || [ "$platform" = "ios" ]; then
+    echo "==> Verifying iOS goldens…"
+    (
+        cd iosApp
+        xcodebuild test \
+            -project honeyDue.xcodeproj \
+            -scheme HoneyDue \
+            -destination "${IOS_SIM_DESTINATION:-platform=iOS Simulator,name=iPhone 17,OS=latest}" \
+            -only-testing:HoneyDueTests/SnapshotGalleryTests \
+            2>&1 | tail -30
+    )
+fi
+
+echo "==> All snapshot checks passed."